Response to the Letter from Prof. Wiwanitkit (RET Genomic Variants in Infantile Hypertrophic Pyloric Stenosis)

We appreciate the comments of Prof. Wiwanitkit, and are in full agreement that our data regarding RET in hypertrophic pylorus stenosis infantile hypertrophic pyloric stenosis (IHPS) are very interesting.

However, contrary to the statement in his letter, our investigation did compare the results of a complete sequencing of genomic RET in IHPS patients with those of a control group of healthy subjects, hence validating the implied risk (or role) for RET variants in IHPS, albeit in a small cohort. Furthermore, the aim of our investigation was to ascertain whether variants in candidate genes were present (which they were) and associated with the phenotype (which they were not, at least not conclusively) in IHPS. “Other genetic factors” is a broad and vague description of further studies which undoubtedly could have been performed, yet were not the scope of our investigation at that time. We are currently expanding this project through a genome-wide association study investigating further links between candidate and other genes (including NOS1 [nitric oxide synthase 1] and motilin) in IHPS. Finally, we do not agree that “no statistical association implies no role”—only 20 to 30% of Hirschsprung's patients show variants in the RET protoncogene, yet the role of this gene in the development of Hirschsprung disease is unquestionable and common knowledge among pediatric surgeons and geneticists. Thus far, IHPS cannot be explained by a single gene defect, which precludes the suggested dismissal of a large number of polymorphisms, mutations, and significant linkage disequilibrium (such as those of RET promoter variants in IHPS) as being a part of a complex multifactorial genetic background for IHPS simply due to the lack of statistical significance in a small cohort.

Conflict of Interest

None